Process of manufacturing lactates.



UNITED STATES PATENT OFFICE.

ALAN'A. CLAFLIN, OF CONCORD, MA KSSACHUSETTS, ASSIGNOR TO LACTIC PROCESSCOMPANY,

' A'CORPORATION OF NEW JERSEY.

PROCESS MANUFACTURING LAGTATES.

To all whdm 'it may concern:

Be it known that I, ALAN A. CLAhLIN, a citizen of the United States ofAmerica, residing at Concord, in the county of Middlesex and State ofMassachusetts, have invented certain new and useful Improvements in theArt of Manufacturing Lactic Acid, of which the following is aspecification.

This invention relates particularly to the manufacture of lactic acid bywhat is known as thefermentation process which may briefly be describedas follows The raw material for this purpose is starch which has beenconverted by well-known methods into the fermentable sugars, such asdextrose, leevulose, maltose, etc. These may conveniently be designatedby the generic name of glucose. A solution of such glucose constitutes afermentable Wort which is set into action by impregnation with bacteriasuitable for inducing the fermentation resulting in the production oflactic acid. But inasmuch as the presence of free lactic acid beyond. arelatively'small amount in the solution tends to obstruct the progressof fermentation, it is customary 'to neutralize the excess of such acidby introducing into the solution at proper intervals an alkaline reagentin suitable quantity. I Calcium carbonate is commonly used for thispurpose. Hence, at the termination of the fermentation by the exhaustionof the glucose, there results from theprogressive neutralization of theexcess. of lactic acid, a final solution wherein such acid exists mainlyin the form of neutral lactatewhich in the case specifically mentionedis calcium lactate. This solu-' tion is then concentrated by evaporationand is afterwards treated with sulfuric acid to decompose the calminimum\the needed subsequent evaporation; yet' experience has shown that insolutions containing much over ten per cent of glucose the lacticfermentation proceeds very slowly and is by reason of such slownessexposed to danger of infection from noxious bacteria. Accordingly themanufacture of lactic acid in the most approved form practiced before mypresent in vention, has been carried on in a fermentation-solution Icontaining about ten per cent of glucose, which after being suitablyimpregnated with lactic bacteria, and allowed to ferment untilexhaustion, while excess of free lactic acid has meantime been preventedby con-.

current neutralization, has resulted in the' production of a solution ofneutral lactate containing approximately Specification of LettersPatent. Application filed June 14,1907. Serial No. s7s.915.

Patented July 23, 1907.

ten per cent of lactic acid, but somewhat less than that because inpractice the yield of lactic acid is never exactly equivalent to theamount of glucose originally present. The solution of neutral lactatethus obtained needs to be concentrated until it contains about twentypcrcent of lactic acid, in order tofit it foreconomical decomposition andto make it yield a product of sufficient strength for commercialacceptability. Such concentration is effected by evaporation in a vacuumpan, but this in turn gives to the resulting solution an undesirablydarkened color which injuriously affects the appearance of the finalproduct. 7

By my invention I obtain the desired augmentation of the proportion oflactic acid contained in the solution without resorting to evaporationand I save thereby both time and expense while securing an improvedproduct. This I accomplish as follows:It is to be noted at the outsetthat for the most efficient practice of my improvement the temperatureof the fermenting solution should, throughout the entire course offermentation, be kept well up towards the maximum which thelactic-bacteria can endure without detriment to their vitality. I havefound that a tempera ture of 135 Fahrenheit is not too high forsatisfactory ing from forty to-fifty per cent of glucose, and they arerepeated until the total quantity added is approximately equal to theamount of glucose originally present at the outset. After thisreplenishment has terminated the fermentation isstill continued untilthe remaining glucose has been fully exhausted when the total quantityof lactic acid produced and neutralized will have reached a proportionequal to about twenty per cent of the resulting. solution. The productis then ready for the usual decomposition and filtration, and thesolution of lactic acid thus produced not only has the consistency ofthe ordinary commercial article resulting from concentration byevaporation, but is also of lighter color and better appearance thanthat.

Of course, it is, obvious, that my herein described method of augmentingthe proportion of lactic acid contained in the product resulting fromthe formation of lactic acid by the process of fermentation and theconcomitant neutralization of the same, admits of lactate present in thesolution, and since'it is imperative that the neutral lactate shouldremain completely/ dissolved'in such solution, the amount of possibleaddition to the fermentable material will diminish. in proportion to thedepression of temperature which determines the degree of solubility ofthe neutral lactate before reachingfthe point of saturation.

'I'claim:

1. In the process of obtaining neutral lactate by the lacticfermentation of a wort suitable therefor and the concomitantneutralization of the lactic acid with alkaline reagents; the method ofaugmenting the proportion of lactic acid contained in the product, whichconsists in introducing into-the fermenting solution additionalfermentable material, as the quantity originally present therein becomesdiminished by fermentation.

2. In the process of obtaining neutral lactate by the lacticfermentation of a wort suitable therefor and the concomitantneutralization of the lactic acid with alkaline reagents, the method ofaugmenting the proportion of lactic acid contained in the product, whichconsists in introducing into the fermenting solution additionalfermentable material in such quantity as to maintain at the time ofintroduction a proportion of fermentable material not substantiallygreater than that present at the outset, and so proceeding until thetotal amount to be finally subjected to fermentation is sufiicient to.produce the desired percentage of lactic acid.

3. In'the process of obtaining neutral lactate by the lacticfermentation of a wort suitable therefor'and the concomitantneutralization of thelactic acid with alkaline reagents, the method ofaugmenting the proportion of lactic acid contained in the product whichconsists in starting with a solution containing at the outset about tenper cent of fermentable material; thereafter introducing into thesolution from time to time additional fermentable material fermentationuntil the quantity so added shall have amounted in the aggregate tosubstantially as much more as that originally present; and thencompleting, the termentation of whatremains, while maintaining the temperature of the solution within the limits of from about 125 to about135 Fahrenheit.

ALAN ,A. CLAFLIN.

Witnesses:

Gnonen L.'ROBI-1RTS, FLonnNcn A. COLLINS.

-to supply the place of that which has already undergone-

